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MANDKLIC ACID                              205

is poured out into a mortar which is placed in the fume cup-
board, the window ot which is drawn down so as to protect the
face, rive grams of sodium are introduced in small pieces, the
size of a pea, and pressed with a pestle under the surface of the
mercury. Kach piece dissolves with a bright flash. The
amalgam is poured out whilst semi-fluid on to an iron tray,
broken up, and kept in a wide-necked stoppered bottle.1

The cinnamic acid and water are introduced into a strong
beaker or bottle (300 c.c.), and the liquid made slightly alkaline
with caustic soda, which dissolves the acid forming the sodium
salt. The sodium amalgam is added in small pieces from time
to time and the liquid thoroughly agitated. The solution, which
remains clear, becomes slightly warm, and the amalgam soon
liquefies, but no hydrogen is evolved until towards the end of
the operation. When the whole of the amalgam has been
added, and bubbles of gas cease to be given off, the solution is
decanted from the mercury, which is rinsed with water. On
acidifying the solution with hydrochloric acid, hydrocinnamic
acid is precipitated as a colourless oil, which solidifies on stand-
ing. It maybe recrystalliscd from a large quantity of warm
water. Yield, 8-9 grams.

7V^/vr//V.v. Long colourless needles; m. p. 47 ; b. p. 280;
soluble in water and alcohol ; volatile in steam. See Appendix^
p. 306.
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PRKP A RATION   96,                                                           jfl
Mandelic Acid, C0Mfl.CH(OH).COOH                                   ||
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Friedliinder,  Thccrfarbcnfabrikation IV,  160.                                   fit ;-
15 grins, benxaklehyde.                                                                         |- \
50 c.c. cone, sodium bisulphite solution.                                                if \
12 grms. potassium cyanide (in 20 c.c. water).                                       if p
The benxaklehyde and sodium bisulphite are mixed together                      I j
and stirred.     The  mixture  forms  a  semi-solid  mass  of the                      1 \
1 If larger quantities uf amalgam are required, the mercury is heated in a small                            if f
enamelled pan, or crucible, the sodium added, in one lot, and the vessel immediately
closed with a ltd, which is held down with long crucible tongs until the reaction is
over, and then poured out whilst fluid.